We will continue our synthesis of deuterated amino acids and incorporate them into gramicidins and oxytocin. We will perform double resonance, difference nmr and spectral perturbation studies to obtain a complete spectral analysis of these molecules in severa solvents. We will perform a conformational analysis based on our nmr data and analysis and correlate our structure with other physical data. We will relate our structure to biological activity. We will repeat this effort in analogs of oxytocin of differing sequence and behavioral or biological activities to determine which sites are important in this area. We have begun to explore other brain peptides, proteases and homogenates. This will be continued along three lines: (a) a study of enkephalin and other morphine agonists and antagonists, (b) a study of lipotropin and its fragments, and (c) development of techniques for purifying and studying components of brain homogenates.